The present invention relates to an emitter-follower circuit and, more particularly, to an emitter-follower circuit suitable for use in an output stage of an emitter-coupled logic circuit (ECL), in which electric charge due to a load capacitance can quickly discharge thereby enabling a high speed switching operation.
An emitter-follower circuit is widely used as an output means in an emitter-coupled logic circuit since such an emitter-follower circuit has a low output impedance and high driving capability to a load capacitance. However, in an emitter-follower circuit having a resistor as a terminator, the output impedance at the fall of an output signal level is quite large as compared with that at the rise of the same, which presents difficulties in achieving a high-speed switching operation at the fall of the output signal level.